Composite floor system

Abstract

A composite floor system includes a plurality of joists, each having a top and bottom chord and a web in the space between the chords. The top chord is formed with a pair of horizontally extending legs and at least one vertical leg. The top of the web is attached to the bottom surface of the top chord. Metal decking is supported by the horizontal legs of the top chord of adjacent joists and a concrete slab is poured on the decking and encloses the vertical leg of the top chord.

What I claim is: 
     
       1. A composite concrete floor system comprising a plurality of metal joists, said joists having a top chord, a bottom chord and a web comprising tension and compression members in the space between the top and bottom chords and secured to said top and bottom chords, the top of said web being secured to the lower surface of sid top chord, said top chord having two horizontal legs and a vertical leg having a lower end and an upper end, deformations formed in the vertical leg between the upper and lower ends thereof such that there is no decrease in the height of the vertical leg along its length, said deformations extending laterally outwardly from said vertical leg, metal decking material supported between the horizontal legs of the top chords of adjacent joists, a concrete slab formed over the metal decking and the top of the joist in which the top chord is embedded with the deformations extending into said concrete slab, reinforcing mesh embedded in said concrete slab such that axial forces on said top chord which cause said deformations to act as wedges tending to split the concrete slab are counteracted by transverse restoring forces created by the reinforcing mesh. 
     
     
       2. The composite floor system of claim 1 wherein said deformations form arcuate projections extending from said vertical leg. 
     
     
       3. The composite floor system of claim 1 wherein said projections are formed approximately midway between the upper and lower ends of said vertical leg. 
     
     
       4. In a composite floor system including a concrete slab floor having reinforcing mesh embedded therein, a vertical member embedded in the concrete slab, said vertical member having deformations which extend outwardly from said vertical member into said concrete slab such that axial forces on said composite floor system cause said deformations to act as wedges tending to split the concrete slab counteracted by a transverse restoring forces created by the reinforcing mesh. 
     
     
       5. The composite floor system of claim 4 wherein said deformations form arcuate projections extending from said vertical leg. 
     
     
       6. The composite floor system of claim 4 wherein said vertical member has an upper and lower end and said deformations are formed approximately midway between said upper and lower end.